The batteries are hooked up right, if they were not hooked up correct then sparks would have flew. What I want to know is would it be okay to bolt the two cables that come off the inverter together. I will not have enough room on the battery post for four leads. I can also charge the new bank of batteries with the converter on the camper but I prefer not to do that. My charger is 40amps and I think that will be enough. I am going to install a 70amp converter in the camper.

Of course the question is which are the positive and which are the negative. On the left you have a separate line going to each negative and the two positives hooked together. The red shrink on the left is confusing virtually everybody...that's why a little red tape would make the whole thing better.

Yes, you can hook the negatives together at the batteries, at the switch or at the inverter or charger. Doesn't matter. In you other installation, the negatives are hooked together on one of the posts and the wire from there goes to the chassis.

Forget the switches on the negatives, put your negative lead on one of the negative posts on the left and run a wire to the other negative post. This does, however,mean that the battery with the negative on its post will get a little more loading, but since you are not using them together that should be ok. However, when you charge them there will be one slightly "loafing" battery...the one that gets a little less loading. Using your method of running separate positives to each pair, there is no way to fix that. Normally when the two pairs are connected together, you put the positive line on one pair and the negative on the other. That way the cable length is the same.

I am thinking that on my inverter with the two positive cables I could hook both up to one battery disconnects and then run one cable to the batteries and do the same for the negative side. The negative side is not the problem.

Really best to have red cables to positive and black cables for negative. With all one color chance for an error is great. Tape helps but is not as good as red cables

Tough to do this UNLESS you have a red on one end and a black on the other. In his pics, he has the top two in series and the bottom two in series, and then each of these pairs are in parallel.

UPDATE: Actually on second view, he DOES have a cable with red on one end and black on the other. He should be using these to hook each pair POS to NEG. Then a red-red pair and a black-black pair to parallel the two sets.

BUT: If he's going to use one of those 1/2/both/none battery switches, it will get even more complicated, as he'll need to wire each series pair to the switch separately.

I wish I had not took the pictures of the batteries. That was not what I was asking about. I have been hooking up batteries for ten years or more. Just forget the batteries. It was really the inverter because of the two positive cables. I don't need any advice on the batteries

The marine industry is slowly changing from Red and Black to Red and Yellow for main power runs to eliminate confusion with 120Vac Black, White and Green wiring. Not good if DC Black Negative touches AC Black Positive - Ouch!

Again, after I get my TT and finish its' installation mods, I'll post. I'll be using Red and Yellow.